OTL/Trans switch on the ASL MG Head OTL
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Orpheus

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Hi. I am completely comfused about the front panel of the Antique Sound Labs MG Head OTL. If someone could tell me what the OTL/Trans switch actually does... you would think that OTL would be to listen to the OTL output and Trans is for the transformer output, but as I understand it, one setting is to listen to feedback of something, or so says Divertech's rep. I wasn't sure what he was talking about though. The switch doesn't seem to do anything when I plug into the OTL jack, but when I plug into the "headphone" jack, the OTL position raises the volume a lot. Can someone explain to me what the switch does and what the jecks are actually for too? Which jack and switch combo do I plug into for the OTL experience?

Also, it does not seem like the case is constructed very well: the feet are not level with each other, and the front faceplate was installed crooked. I was able to put a washer between one of the legs and the platform to make it stand straight, but the faceplate is impossible to fix cause the holes for the switches and jacks were drilled crooked too. Does anyone else have this problem?

Well, the workmanship's pretty bad, but the amp sounds alright (except for the annoying buzzing)... so I guess it's okay.

Dean
 
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RGA

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Hey don't stand for that.

If the thing doesn't balance right and the faceplate is incorrect then maybe the inside has problems.

I have the non OTL version and it it is dead quiet and very solidly built. You have to realise that this amp is ASL's biggest seller contantly on backorder and they likely feel the pressure to rush them out the door.

And they sound very good for the money. That said, it's not fun to make a purchase(for me as a student this was a LOT of money) that you are not 100% happy with.

It is not unreasonably to argue that because the unit is not balanced correctly the sound suffers...after all they sell high priced feet for amplifiers to IMPROVE sound. Whether you or I buy into that does not change the fact that it is an argument people use and sellers use to get those feet purchased.

ASL comes with a 5 year warranty...Use it. It's unfortunate but the MG Heads have a number of people that get these less than perfect units...only you can get it rectified though so press the issue.

They SHOULD want you to be very happy - after all you may consider buying an amplifier for your stereo one day...chances are if you get good service and a good product then you'll consider ASL again. They're first on my list for a future integrated or power amp.

You may want to mention all of this to your dealer - they want repeat business they better make you happy.

It should not buzz and it should not tilt back and forth...and the front panel should be reasonably strait. You can't expect perfection as they are built by hand...but it should not be lopsided


Use the Warranty...it's a great amp when all goes well.

I don't have the OTL version, but the High Low switch does very little on my amp. OTL supposedly improves bass if you're using the HD580 or 600. I also understand from my dealer that in OTL mode it muddles the midband a bit in order to generate more bass. I think it has enough bass without OTL but oh well.
 
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jerikl

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For OTL to sound good, you really have to upgrade your tubes... or so I hear. I've always had upgraded tubes. If you do some tube rolling the MG Head will probably make you much happier. If it does not sit up straight, contact them and they'll probably fix it no charge. If you do not want to wait for it to get shipped/fixed/shipped back, go with your mod
The MG Head has just not been beat yet in it's price range. I have listened to a few other tube amps costing quite a bit more (Earmax Pro, RKV, Twinhead) and they are just not all that much better. Sure, they all beat the head in just about any category you can come up with, but they are not good enough to justify the purchase at the price they are offered for me. Now, if you have some money to throw around, go for it... but I don't. The RKV at $700 a few weeks ago I might have done though. That was a good deal.

Oh, and BTW, my faceplate is off-center too. And, the right EL84 tube socket is not level... so the tube leans to the right. But, I really don't care, as it sounds great.
 
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fredpb

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The OTL output does not use the transformer as an output device, but as a "plate load" inductor. Greek? It just means that, no transformer output, it is a direct output. No transformer is used in the signal path. The switch will do nothing to this jack.

The Left or Transformer out jack DOES use the transformer as the output coupling device....signal goes through it. The transformers I am talking about are the two big black square cans on back of the MG Head.

The switch is used with the transformer output. It turns "negative feedback" on and off. The output signal is picked off the transformer stuff, inverted, and fed back into the beginning of the circuitry. It will reduce the volume considerable as it is the exact opposite of the signal. The circuitry does add some coloration or distortion to your signal. The original input signal does not have this. So a lot of the feedback cancels out a lot of the created noise or distortion, making a lower volume, but "cleaner" signal.
 
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Orpheus

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thanks fred.... the manual that came with the thing really said nothing. dunno why they even bothered including that stupid manual. anyway, i understand now.

..........and thanks to the rest of you. 5 year warrantee huh? cool.... that crooked faceplate is pretty darn off center.... one side is almost a centimeter lower than the other! and the buzzing is pretty loud when i use the otl jack position with the transformer output. well, i've been trying to call Divertech, and I haven't been able to reach them the last 30 times or so (at various times in the last couple months) i called........ i dunno. if it weren't for the fact that this is pretty much the cheapest tubed headphone amp on the market and that it sounds pretty good despite the buzzing, ASL really should get their act up to par.

oh, and i know the buzzing isn't cause of the electricity i fed it... i have a Furman IT-1220 isolation transformer balancer that's protected by the Furman AR-1220 voltage regulator. i was actually comparing my brother's Corda amp next to the MG Head, and with the Corda's volume turned all the way up, it was still dead silent. no buzz or noise on that unit. but the buzz was noticeable with no volume on the MG Head and with the knob turned all the way up, it was almost like 20-30db of buzz! both units were fed the same signal, at the same time, splitted at a patchbay (i have a recording studio.)

anyone else have problems with crooket faceplates, uneven feet, or other deformaties?

dean
 
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grinch

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yeah, the build quality is really ****ty on my mg head dt. the first one i got, the mini-jack did not work.. and since this was my first purchase in the world of headphone amplifiers and a lot of money for me (at the time, before i became addicted
) i was quite disappointed. headroom sent me a new one very quickly though so it worked out fine.

however, sometimes it buzzes when i touch any part of the metal chassis. also, it picks up rfi better than any other amplifier i've ever used. the mini-jack no longer works on this unit. also, i bought the mg head under the silly idea that it can drive different kinds of headphones well.. which is a big fat lie. it only works anywhere near decent with the hd580/600, although my etys are okay with it. all in all, i may sell the bastard once my rkv comes in the mail.. i only still have it so i can keep a crappy i-don't-care-what-happens-to-it amp at work.

it really bothers me that this amp gets such rave reviews.. maybe if i spent $450+ on tubes for it, it'd sound amazing..
 
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jerikl

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whoah grinch. Sounds like you have a couple things wrong with your MG Head. But, if everything is working right, the MG Head is one great amp. yeah, the MG Head's do seem to have build quality issues, but we need to realize what we are getting for $330. Someone else could probably explain this better than I could. That price is really amazing for what you get in terms of sound quality. I don't know what you were expecting, but if you ventured out a little bit and spent about $30 on tubes, you could really improve the sound of the Head. Get yourself some JJ EL84's and a Sovtek 5751, all current production tubes. Or, get some NOS 12AX7 tubes or whatever variations (5751, 12AU7, 7025). Sorry about the mini-jack... I agree that I'd be kind of bummed if something on my amp didn't work too, but it should be an easy fix.

You're right about the MG Head not driving many headphones well. But, I disagree with you about how it drives the HD580/600's. I think it does damn well. Compared to the Earmax Pro/RKV/Twinhead, it is just not THAT far behind. And, at several hundred dollars less than each of those, it's a real bargain. Maybe you should come hear mine or something... might change your opinion of them
 
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Nick Dangerous

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There's a pair of NOS Sylvania Gold Brand 5751's on eBay right now.

Unfortunately, they will not be cheap.
 
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Orpheus

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i think the issue here is the quality of the product. many people out there are willing to say... spend twice as much for a sony product compared to a comparable... say JVC solely because of the name and the accompaning percieved quality. now, if ASL cannot produce a quality product, no matter how good it sounds, for $300, then they shouldn't charge so little. a good company does not take short-cuts, and does not rush to ship units that do not meet universal standards. even that stupid buzzing in the left channel should have been easily fixed during the engineering phase had they taken the time to test their designs. a company that makes $5000 tube amps should not have crooked faceplates, uneven feet, and broken sockets, even in the cheapest of their lineup. if they need to raise the price of the MG Head so that they can produce their products with the same quality workmanship as their competitors, then that's what they should do.

who wants to pay $5000 for their top-of-the-line amps when they can't even get their cheapest products right?

orpheus
 
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lextek

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I've owned two MG Heads (soon a third) and never had any of these "problems".
 
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Orpheus

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Well, I am going to send in my unit today. Hopefully they'll send me a replacement without defects.

I hsould note that my unit was actually one of the first OTL's made... it was shipped without the tube cage, and I was told by Divergent that only the first units were shipped like that. Maybe the newer units are made better.

Gonna pray.... heh he

Dean
 
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fredpb

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I have one of the MG Head OTL's without the tube cage.

I have done moderate tube rolling, replacing the output tubes with the JJ Teslas and I also replaced the single tube twice.

I did have a problem with mine for a while. A little static noise sometimes in the right channel. I talked with Divergent about it.
They gave a few suggestions.

But I did a minor trick with mine, which I don't recommend. I wiggled the tube halfway out a bit and it cleared up the problem. It was either dirty connections or a bad connection/solder joint, and seems to be ok now. You can't troubleshoot something that is not now there, so I will keep it and hope it does not repeat the problem.
 
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fredpb

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Quote:

Originally posted by Orpheus
so which switch/jack combo is supposed to sound the best overall?


Purely a matter of what headphone you have and your own individual taste.

I personally use the transformer out (left jack) with feedback ON/IN. This is for the HD600/Clou red combination.

You may find different jacks sound better with different music.
For slightly more bass, the OTL, for more detail, the transformer out.
 
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fyrfytrhoges

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orpheus- I just recently received my MG Head OTL and after looking at it closely I have noticed that my amp too has the same problems as yours, the faceplate is slightly crooked and the feet are also not level. As well as the lettering on the faceplate, it is not very good quality. However I have to say that I am not having any sound quality problems which to me is the most important feature. But I will agree, that whether or not a company is backordered or pressured for orders, it should still produce a quality product no matter what.
 
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